Electron discharge device



00 7 1. QW. .E u A., 5. RC W. 2 t ON l N .T0 R .h Non m S E 2 2 Wl- Alm r. /M F V/ E B C I V E D m m o m R w v I L D V. w mm m y L E 8 3 5 3 /l w .4 O' HARQm/.w d 4 m, w v9 m 1a S 9 m m -Hn a u n 2 J F June 1, 1948. v. L. RoNcl ELECTRON DISCHARGE DEVICE 2 Sheets-Sheet 2 Filed Sept. 24, 1945 /A/ z/E/v TOR M L. RONC/ ATTORNEY Patented June 1, 1948 Yanne,` N. Y.; co'rgation 'f New York Applictien september 24,1945, serial No; 618344 Thisinventiori relates, t0. eletlon.Qishargeglef vices-and mere particularlyto sucbdevieesnfthe multigri-d type and especially suitable for use aS power amplifiers. :Iri certain multigrid tubes.; tl1e eQntrQ1 ,an;d Screen grid. ,electrodesLhave been pasitaiiedmthe dseiiaree; path between the;eathodeaadraaode with-their laterale or grid turns, in aliaiiment. `sa that Vthe .controierid acts as ashield fertile sren'etd, t0 reduce the;.sereemailidecilrreet A,Other advantages ofthe,.alierieagriti eleQtrQdes are, teinoreasethe. operating range. t. @reame Oithesereen grid, tQ prQ1Q1rg life aaa :to provide mgrexeicient performance of the device asia-modulator. However, in such. 'devices .@Qrtsiderab1e-vdiiculiy hasbeen experienced in' maintaining stabl arid reproducible static and dynamic .characteristics iiifthe deYice overallv extended period 0f. lifetime to Ythe disturbance 0fA the alignment@ the.. arid electrodes either because, Qi temperatureehanges Q remechanical instability of the supporting strucliereteierap it. haa been .aerial to.tr1 ot1,r 1t.t.i 1.e eriaeleetrodes aligned relatien and. maintain them iiietilch .pesitieirbyiattaqhmerit taonii G- tfii; .stembelow the electrode. uriit. fl `1.1.i$ Qonstrlietia has 'Proretilinsatisfaetaix .heeaue 0f frailty of the Supporta a11 d;a1s0,;l2eai1se .of eraariionethe .coaduetererntier varyiriateinagitare .cpiiditieaemhich .resulted in i.iiirfial'gir meat. aladin, destructive burarolit .ofthe alli@ by.. .eleetren impart- -Tiieetrnetiieaiaapf lthe,S11riporta;at the. lowerlendpf. the in order :.aY'Qid@ the .above gdifiiciilties, cauaect ether deieteriouaeeta' Stich .as .relied leakage re- Siiaria lieber eapaeitaate between. ...tl 1e e1 e f ,trates arid eherteircuitiea ef.. .theY letrdea whichfsteesier the devieeliiiiit for Servite. Il .gbieetf iriveritiait ter verome these deff-Stein maltigrideleetrde device,- Another Q liet @i the, inventien is tO attain ritire collateral relatieriship 0i .tile iii'riieli tliejgwo gridsuoyer ari .exterided period and under varyineeaeratiiig eoiiditiene ...tti if Obie of thenveitii ie t0 feti-litt?? tile ,as'eiiibly 'ef 'the eleetiedeliiitinmultierid dviesariel t0 enable prediietionatlwest .,Titeeobietts are attained in a99il-1 1., e.with features, ithisiiiventieii te agbeam. rqweretyre devichaving a. cathode arid anod mounted be- 35 where tHe 'tweeriaidsiaeer.itieriberatliaiiail.Oilaifliy meuritededeflectsir Rlateaiiiterpiisedb. t @Sallie cathode andanede and axed. tetheendeeaeeis. A.;pair v of helieally waan-d ,grids .Sllrolliid thte 5 eatbodeam diepesetlin uehrelatientathe arterie arialeilecftor ,plates that beams Qilelee: treue V.areprejected.taivartl the Suiiaeesl 9i the anode between the plates. The ur1ii;a1 ;yL ase1`nllly ,et theeleetredes meariteden a pair eid 10 ceridiicterearieboreatog-theleweixspaeeraii the `tiititlis,partially,Submitted fram the sidawallaeai the Ydeyice by eusliiorrepacers extending from both end spacer members. lhe central grid neareet. the ,eathgde ie main- 15 tained. iii rpesitiveelatien e. 9atiiQdeby a not. interfere 'el t paeitaiie .rilrsmer Dig. th electroaes'are free to expand endleritraet umfermlvmder temperaturepiiaaeee. Statie tlieeids handlingwthlt the possibility of Vi;l1e;gr' iS -beirig naisaliguedk Tlreedgemduntirigof the suspension supports eounteraets. thrllsgstressea :affectinagthe .alienmentertbe .eritl electrzdee andthe .erasing tbPeridSWiaQitie "elqseet tath Stateside tirera-,- urbjected to heating`by the lntensecathpension support. The projecting vane construction of the edge mounted suspension support is an eicient heat radiation member for the grid and by coating this member with a black body substance, such as carbon, the dissipation of heat from the grid is accelerated so that the grid is rendered relatively cool and emission therefrom is suppressed.

Another feature of the invention relates to the main support of the electrode unit in the enclosing vessel so that excessive expansion of the conductors in the stem does not cause deleterious distortion of the frail grid electrodes in the assembly, which are the structurally weakest elel rThis construction involves the mounting.

the electrode mount through the side spacers at opposite ends of the assembly, and the unit is longitudinally supported by a pair of supports in the stem which areY anchored to the lower insulating spacer. The frail grid electrodes are connected to separate rigid conductors in the stem by light flexible straps and, therefore, are linked to the rigid conductors through yieldable connectors which do not transmit the stress forces applied to the rigid conductors during temperature changes.

These and other features of the invention are set forth in more detail in the following description which together with the accompanying drawings depict one embodiment of the invention:

Fig. 1 is an elevation view of a device made in accordance with this invention with the enclosing vessel and base partly broken away to show the internal structure;

Fig. 2 illustrates in elevation the assembly of the electrode unit or mount incorporated in the device of Fig. 1, with several of the electrode elements shown in longitudinal section to show the relationship of the elements and the supporting structure thereof;

Fig. 3 is a plan view partly in cross-section takenon the line 3-3 of Fig. 2 in the direction of the arrows;

Fig. 4 is an end view of the device illustrating the 'top end position of the unit in the vessel, taken along the lines 4 4 of Fig. 1;

Fig. 5 is a perspective view of a partial assembly of the unit involving the supports of the grid electrodes in accordance with this invention;

' Fig. 6a is an enlarged View in elevation showing the alignment of the grid laterals as accomplished by the mounting assembly of Fig. 5;

Fig. 6b illustrates in cross-section the relationship of the grid electrodes as viewed on line {ib-,6b of Fig. 6a; and

Fig. '7 is a plan layout of the connections between the conductors in the stem of the device and the electrodes in the unitary assembly.

The invention is embodied in a multigrid high power tube of rigid construction to withstand severe usage and operating conditions. Thisconstruction, as shown in Figs. 1 and 2, forms a compact assembly. The tube is equivalent in power output and operating characteristics to a similar tube, not embodying this invention, three times its size, both having the same potential, for example 1250 volts, `applied to the anode or output electrode. The compact assembly is capable of withstanding high gravitational shock, both laterally and longitudinally, so that severe shock encountered in operation will not cause distortion 4 of the electrodes and thereby alter the characteristics of the electrode assembly.

Referring to Figs. 1 and 2, the device includes a cylindrical vitreous vessel or receptacle IIJ having a molded dish stem I I joined to the lower end and in which the leading-in wires or conductors I2 are sealed for conduction of electrical energy to the various electrodes contained in the unit within the vessel. The stem is cemented in a molded supporting insulating base I3 having a series of terminal pins I4 secured in the bottom thereof in a circular boundary to which the conductors I2 are attached for external connection of the device in the appropriate circuit. The base is provided also witha central integral projection I5 for indexing the device in its associated socket so that the terminal pins are connected to the appropriate circuit connections for the device.

The unitary electrode assembly mounted within the vessel includes a central tubular cathode I6 formed to an oval congurat-ion and provided with an appropriate emissive coating for the production of a copious supply of electrons. The cathode is provided with an internal heater I'I, as shown in Fig. 3, embedded in an insulating sleeve I8 extending through the length of the cathode. The cathode is surrounded by a rectangularshaped anode formed of two half sections I9 having outwardly extending ns 23 which terminate in formed sockets to receive support pins 2| extending through end insulating spacer discs or members 22 and 23, for example of mica. The spacer members rigidly x the cathode and anode in coaxial relation in the assembly, the pins 2l extending through insulating bushings 24 in the end insulating spacers and being welded in the sockets of the ns of the anode. In order to strengthen the anode to withstand the high temperatures encountered due to the high voltage operation, the body sections of the bipart anode are provided with deep spaced corrugations 25 running transversely to the length of the sections and the fins are provided with longitudinal corrugations 26 to offset buckling in the metal surfaces. The whole anode assembly may be coated with a black body substance, such as carbon or zirconium, to serve as an efficient heat radiator to dissipate the heat generated in the anode due to the high-'voltage operation.

A pair of beam-forming or deector plates 21 of angular cross-section, as shown in Fig. 3, are mounted longitudinally between the inner anode surfaces and the cathode to shield the short sides of the anode and thereby increase the projection of electr-ons from the cathode in a definite path toward the broad sides of the anode. whereby the productionof beams of electrons is facilitated. The deflector plates 21 are mounted in opposed relation on opposite sides o the cathode with their open ends facing toward the cathode and are rigidly held inY position by pairs of rods 28 welded to the inside corners of the pates. The rods 23 have extensions projecting through metallic eyelets 29 secured in the 'end spacer members 22 and 23 and welded'to the rods.

The location of the electrodes inthe assembly is completed by the mounting of the `grids coaxially surrounding the Vcathode with the laterals of the two grids aligned in accurate transverse relation in the direction of electron flow from the cathode to the anode. In order to maintain accurate alignment and to secure stable operating characteristics regardless of temperature 'changes or rough usage of the device, the gridsare supported in accordance with one of the main featuresl'of this :invention so that true alignment of 7the-laterals of the two grids xis i'mainta-ined oonfstant throughout 'the operating llife zof the device. The control grid for the 'grid nearest the cathode is the 'for-m of :an oval helix -3|l, of email diameter wire but of great strength,=suoh as molybdenum wire, supported by a pair of upright rods 3| positioned'at the extremities of lthe oval. The second or *screen :grid 32 lformed of similar wire and supported by Aupright rods 33. Both grids fare wound lwith the same :pitch but of Adifferent diameters, as shown in Figs. 6a and :6b fand `are supported Pooaxia-lly faround `the cathode and between theiend Vspacer discs 22 land 23 so that all the later-als `are valigned in a trans-verse direc- 9tion between the emitting surfaces -of the cathode and the receptive surfaces -o'f the anode. Since the grid electrodes 4are placed close to the cathode it -is preferable =to provide the grids with a 'non-emissi-ve coating,-such as a metallic @platinglof gold, to maintain .the grids conductive yet render the grids non-emitting. Furthermore, heat from the -grids is accelerated by `forming the upright rods of good heat conducting material, such as Acomzwer -or a copper valloy having greater strength. i

Intorder tomaintain the .grids 'in lateral aligned relation, the `end. `portions of the 'upright rods of the control grid extending through the top insulato'r spacer '22 are secured to a symmetrical frame member which is anchored tothe top insulator to provide a rigid suspension support. One vembodiment of '-thissuspension support 'is =a rectangular shaped frame member or vane, 'preferably'formed of two sect-ions to facilitate attachment to the grid uprights and the supporting-assembly on the top 'of the unit. These sections, as shown more clearly in lFig. 4, are a pair of angularlybent relatively wide strap members 34 and 35 having mid-point loop portions 36 which Vsubstantially embrace and are secured to the projecting ends of the upright rods 3| ofthe control grid. The opposite ends of both frame-members are bent outwardly and formed into half socket portions 31 and when brought together, as shown in Fig. 4, the end portions -31 form sockets -to embrace stationary pins 38 projecting from and riveted :to the top insulating spacer 22. The pins are laterallyin line with and project from the spacer parallel to the axis of the cathode I6. In addition tothe rigid suspension support of the grid afforded by the frame, the symmetrical `trame Imemberextending above the unit serves as an eiiicient heat radiator for dissipating the heat absorbed by the grid. By applying a black coating to the frame member, such as a coating of carbon or zirconium similar to the coating on the anode, the dissipation of heat from the grid by radiation is increased. The screen grid 32 is suspended from the top insulator assembly by a pair of edgewise mounted straps 39 and 40 which extend transversely above the spacer disc 22 from the ends of the grid rods 33 and are secured to rivet pins 4I secured to the spacer 22 after proper alignment of the two grids, as shown in Fig. 6a, the pins 4l being mounted at oppositely disposed points in line with the cathode and grid supports across one axis of the spacer disc 22.

The rigid suspension support of the multigrid assemblies of this invention insures a shock-proof mounting whereby the two cooperative grid electrodes are positively held in constant lateral relation to each other so that the turns of the grid are in laccurate alignment and maintained in such. position regardless of temperature variations or other changes aectng the electrodes: -It will be noted that the grid .supports .extend 'through-the lower insulatingspacer 23 'and are' free to expand and contract uniformly vwithout altering the aligned relationof the laterals-ofthe grids. 'Ther-symmetrical anchormounting-iof the grids rrom theftop insulating spacer-also avoids introducing deleterious capacity effects vwhich would -be liable gto occur -if the mounting -support of fthefgri'ds were Jlocated at the bottomofhtle wassembly where vthe structure mightinteriere with the conductors -to the various electrodes,

-fnfaddition to the rugged y assembly `providedby the unitary mounting of the electrodes irraccordance with thisjinvention, .the -`mit `withstands severe shock lboth iaterally and longitudinally, so `that service conditions are not apt to endanger -t-he structure by distortionrior stresses `due to severe shook. Lateral distortion is over-.come by mounting the unitifrom the side `wal-ls for thecy- -lindrical vessel l0 by side mica spacers 42.1ocked onears -43'=extend.ing at three equally spaced-.positionson both Imicaspacers2f2 and 23, to-.resiliently cushion the 'enti-re Yunit within-the enclosing vessel land protect the unit from lateral shocllrlirniparted -to the vessel. In -addition, the unit is mounted from the stem r`to withstandflongitudinal shock vby a pair of rigid `conductors t2 extending through .and attached in eyelets secured in the ilower Vspacer member 23 asshoWn inFig, 2. The supporting `.conductors I 2 .extending .to 'the Vlower spaoerf23 also serve eas Icur-rent conduotorsiforlcertainelectrodes, i. e., the longer supportwrod A33 of ,the `screen grid is connectedwlto theileft-hand `support rconductor, -as shownin i2, by alight `flexible conductor 44 while theA rightghandfconductor is connected by abentfstrap -.to-.arpair Aof the support .rods 28 Sor the ldeilcotere. plates. The-cathode is coupled to the strap 45 byla ilex- .ible A`connector '46 l*so that the cathode fand-the deflector plates-are fat the same potential, which is nominally aero. The heater ofthe cathode is 1connected V-to a pair-of leading-in conductor-sn lbyextending the conductors up to the end of .the tubular insulator .I8 vand ,attaching` these `conductors to the ends of the heater. The control grid yit!) fis yconnected to the remaining conductor `in the stein l'by Ia light `flexible strap e4-1.", The istraps ,from the 'conductors Lto 'the vmultigrids` in theunit -a-re made relatively flexible so that-the grids y.can expand and'contract withoutdanger o! the transmission Aof Iexpansion stresses being Aimpartediby-theconductorsinthe stem. n

LSince the `top and bottommicafspacersiand 23 are substantially similar except for the pins projecting from the top mica and the eyelets in the bottom mica for the supporting conductors, it is difficult to select the proper pair -of spacing micas from a supply tray in assembly and, accordingly, it is one of the features of this invention to facilitate' the selection of the proper pair of spacing insulators by the provision of indexing holes 48, as shown in Fig. 4, for the upper spacer and 49, as shown in Fig. 3, for the lower spacer. When these holes are aligned, it is an indication that the proper pair of spacers are being applied to the assembly. If the holes do not register when an indexing rod is passed through the micas at the beginning of the assembly, the operator will immediately be aware of the selection of the wrong pair of spacers and the mistake can be rectied before further assembly is attempted. While the invention has been disclosed with respect to a specific beam power device, it is, of course, understood that the invention may be applied to other types of devices lof the multigrid type without departing fromthe scopeand spirit of the invention as dened in the appended claims. f

What is claimed is: y

1. An electron discharge device comprising an enclosing vessel, an electrode mount Within said vessel including a cathode, anode and a pair of grid electrodes in coaxial relation, insulating spacer members at opposite ends of the electrodes, and suspension means supporting said grid electrodes from the upper spacer member with the laterals of said grid electrodes in transverse alignment.

2. An electron discharge device comprising an enclosing vessel, an electrode mount assembly within said vessel including a cathode, anode and a pair of grid electrodes in coaxial relation, said Agrid electrodes having the laterals thereof aligned with each other in a transverse direction, insulating spacer members at opposite ends of the electrodes, and edge-mounted metallic members exterior to said mount assembly rigidly anchoring said grid electrodes to the upper spacer member.

3. An electron discharge device comprising an enclosingV vessel, an electrode unit supported Within said vessel including a cathode, anode and a plurality of grids in coaxial relation with insulating spacer members at opposite ends thereof, said grids having their laterals in accurate alignment in the direction of electron ilow between said cathode and anode, and means rigidly maintaining said grids in aligned relation including edge-mounted strap members coupled to said grids and attached to supports projecting from the top spacer member.

4. An electron discharge device comprising an enclosing vessel, an electrode mountl assembly supported within said vessel including a cathode, anode and a pair of grid electrodes, upper and lower disc insulating spacers supporting said cathode and anode in coaxial relation, said grids each having a pair of support rods extending -through said spacers, a pair of pins projecting outwardly from said upper spacer in line with said support rods, a second pair of pins extending from said spacer laterally in line with the axis of said cathode and in transverse relation to said rst pins, a symmetrical strap member embracing the second pair of pins and a pair of support rods for one of said grid electrodes, and a pair of bridging strip members attached to said other pair of support rods and said rst pair of pins.

8 5. An electron discharge device comprising an enclosing vessel, an electrode mount assembly -supported within said vessel including a cathode,

anode and a pair of wire wound grid electrodes, said grid electrodes having their laterals in alignment in the direction of electron flow between said cathode and anode, upper and lower insulating spacer members supporting said cathode and anode in coaxial relation, said grid electrodes having upright rods extending through said spacer members, and means rigidly suspending said grid electrodes from said upper spacer member whereby both grid electrodes can expand in unison through said lower spacer member, said means comprising support pins extending from said upper spacer member and symmetrical strap connectors in edgewise relation extending between said support pins and said upright rods.

6. An electron discharge device comprising an enclosing vessel, an electrode mount assembly supported within said vessel including a cathode, a pair of defiector plates, an anode, and a pair ofgrid electrodes, said grid electrodes having their laterals in alignment in the direction of electron iiow between said cathode and anode, upper and lower insulating spacer members supporting the electrodes in coaxial relation, means rigidly suspending said grid electrodes from said REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Nam/e Date 1,605,001 Schroter Nov. 2, 1926 2,178,836 I Krahl Nov. 7, 1939 2,350,003 West May 30, 1944 FOREIGN PATENTS Number Country Date France July 22, 1935 

